Setting CalDateTime's TzId to a new value does not reset the AsUtc value

[rianjs]

If you call calDateTime.AsUtc and then change the TzId property, AsUtc continues to return the old, cached value.

[Test]
public void TestTzidChanges()
{
    var someTime = DateTimeOffset.Parse("2018-05-21T11:35:00-04:00");

    var someDt = new CalDateTime(someTime.DateTime) { TzId = "America/New_York" };
    var firstUtc = someDt.AsUtc;
    Assert.AreEqual(someTime.UtcDateTime, firstUtc);

    someDt.TzId = "Europe/Berlin";
    var berlinUtc = someDt.AsUtc;
    Assert.AreNotEqual(firstUtc, berlinUtc);
}

[rianjs]

nuget package 4.1.1
https://www.nuget.org/packages/Ical.Net